Mr. Berlusconi's political stability is not being threatened by one of his many sexual scandals of recent months. Instead, the source of his current troubles lies in an editorial in Il Giornale, a conservative daily owned by his brother Paolo.

Last Friday, Il Giornale published a front-page editorial attacking Dino Boffo, editor-in-chief of Avvenire, the daily of the Italian Bishops Conference, which runs the Italian Catholic church.

It accused Mr. Boffo of having had a homosexual relationship in the past and of having made threatening phone calls to his lover's wife. Il Giornale argued that, as a result, he "lacks the credibility to be a moralizer" – a reference to Avvenire's previous criticism of the prime minister's personal conduct.

"This is a huge step; nobody ever dared to attack so openly someone that important in the church," says Paolo Rodari, a Vatican analyst for the conservative Il Foglio. "To attack Mr. Boffo is similar to attacking one of the highest-ranking cardinals: His newspaper is run by the Italian Bishops Conference; it's the media image of the Italian clergy."

Il Giornale published a judicial record, showing that Boffo agreed to a plea bargain that required him to pay a €516 fine for the phone harassment of the woman. It could not provide, however, any proof about his alleged homosexuality.

Boffo denies both allegations and says he accepted the plea bargain just to avoid trouble. But despite outrage, the paper has continued to attack Boffo this week.

The Italian Bishops Conference dismissed Il Giornale's editorial as a "mafia-style warning." Pope Benedict XVI himself has reportedly expressed his confidence in Boffo, although no official comment has been issued by the Holy See.

The prime minister insists he has nothing to do with the decisions of his brother's newspaper. But the Vatican took it as an attack from Berlusconi himself. The Vatican's foreign secretary, Cardinal Tarciso Bertone, canceled a scheduled dinner with the prime minister after the editorial appeared.

The importance of good Vatican ties

Good ties with the Vatican are considered crucial for any Italian government. "I don't know whether the prime minister was behind the attack or not, but now he is in trouble for sure," argues Mr. Rodari. "It's hard to think that just four days ago, Berlusconi's government had the most idyllic relationship with the Holy See."

Berlusconi's sexual scandals have hurt the prime minister's reputation at home and abroad, but not his ties with the Vatican. "They don't care what he does with his private life, as long as he passes a series of conservative reforms," says Rodari. "The very fact that Cardinal Bertone had invited the prime minister to dinner means the church intended to reassure Berlusconi and tell him everything was fine."

Despite the Vatican's earlier silence, some Italian bishops have criticized the prime minister's alleged misconduct, often on the pages of Avvenire.

Some believe the Boffo affair is harming the Italian clergy even more than it is harming Berlusconi: "While the Vatican itself wasn't touched by this scandal, Avvenire and the forces behind it are losing credibility," says Rodari. "The bishops' conference is coming out of this with its bones broken."